First BAT Burst

SWIFT, NASA's new gamma-ray burst finder, is slowly coming alive. SWIFT's instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT) and the ultraviolet and optical telescope (UVOT) are carefully being turned on and calibrated by the SWIFT team. Even before the instruments have been fully activated, SWIFT is returning scientifically useful data, and some surprises as well. The graph above is a gamma-ray burst (GRB) discovered by the BAT on December 11, 2004. The plot shows time along the horizontal axis and gamma-ray brightness along the vertical axis, and the arrows mark bursts of increased gamma-ray brightness. When fully operational, GRBs detected by the BAT will be localized by the XRT and UVOT, and the data quickly disseminated to astronomers on the ground for follow-up observations. Astronomers look to be quite busy, since the BAT has already seen an unexpectedly high rate of GRBs.